Abstract: A storage system such as a storage array in a data center calculates per-application power utilization based on monitored IOs. IOs generated by applications that are tolerant of rescheduling may be rescheduled to a time when power is less costly or more available. Storage array power consumption is reduced if all services host applications can tolerate greater IO latency without service level violations. Server power consumption is reduced if all services host applications can tolerate greater IO latency without service level violations. Power consumption by the servers, storage array, or both is reduced if power consumption reaches a predetermined level relative to available power.

Abstract: A method for maintaining a detected absolute position of an electric motor operating as an actuator during a critical operation involves the electric motor (2) being controlled by a controller (1) which is supplied with energy from an energy source. In the method, with which an absolute value sensor can be omitted, the absolute position of the electric motor (2) is measured during the operation thereof, wherein rotations of the electric motor (2) are detected. The rotations are counted, and a count value is output to a microprocessor (3) of the controller (1) in order to actuate the electric motor (2), and in the event of a critical operation, the currently detected count value is maintained by means of an independent voltage supply (7).

Abstract: An inverter device includes an inverter circuit that has switching elements configuring an upper arm and a lower arm of each of U, V, W-phases, a signal generator that generates signals having waveforms corresponding to signals of U, V, W-phase command voltages, a first calculation unit that calculates an effective line voltage, a second calculation unit that generates a modulation voltage every control period, and a comparison unit that compares the signals with signals of the modulation voltage every control period, and outputs signals having pulse patterns which operate the switching elements of the upper arm and the switching element of the lower arm in the inverter circuit.

Abstract: A main circuit power source and a control power source of a motor drive device are backed up. A first backup capacitor is inserted between a rectifier and a control power source output terminal that supplies power to a control circuit of a driver.

Abstract: An elevator system includes an elevator car; a machine to impart motion to the elevator car; a brake to stop rotation of the machine, the brake comprising a first coil and a second coil, wherein removing power from the first coil and the second coil applies the brake to the machine; and a controller in communication with the brake, the controller configured to connect the first coil and the second coil in one of a first electrical configuration and a second electrical configuration.

Abstract: An illustrative example embodiment of an elevator system includes: a plurality of elevator cars; a plurality of elevator machines, respectively associated with the elevator cars to selectively cause movement of the associated elevator car, at least some of the elevator machines respectively operating in a first mode including consuming power and in a second mode including generating power; a power source having a power output threshold and a power intake threshold; and at least one controller that is configured to determine when the power source is providing power for the elevator system, and dynamically adjust how the plurality of machines move the elevator cars to maximize a number of the plurality cars being used to move passengers while keeping power consumption by the elevator system below the power output threshold and keeping power generation by the elevator system below the power intake threshold.

Abstract: A control circuit configured to control an electromechanical brake is provided. The control circuit includes: a switching regulator configured to control a magnitude of voltage applied to a brake coil of the electromechanical brake; wherein said switching regulator includes at least one semiconductor switch, one diode, one capacitor and one inductor; the control circuit is configured such that, in operation, at least one signal from a process sub-system specifies the magnitude of the voltage for the brake coil; and at least one brake applying control signal from a safety sub-system can cause the brake coil voltage to be reduced to a level low enough to apply the brake by opening a switch and each brake applying control signal from the safety sub-system has a corresponding diagnostic feedback signal to the safety sub-system that indicates the state of the corresponding switch. A method and a system are disclosed.

Abstract: A method of guiding a coasting time point of a vehicle includes steps of detecting occurrence of an upcoming deceleration event, determining driver's coasting characteristics for each deceleration event based on information of the detected occurrence of an upcoming deceleration event and a vehicle driving state, and determining a coasting guidance time point based on a determined result of coasting characteristics corresponding to a type of the detected deceleration event. The method provides, to a driver, information of a time point at which the driver needs to release an accelerator pedal operation, in order to begin coasting at an appropriate time point when a deceleration situation is assumed to lie ahead.

Abstract: An emergency operating arrangement for at least one building technical device is provided, comprising a power supply unit, and an emergency supply unit, the power supply unit and the emergency supply unit being adapted to be supplied by an electrical supply and being configured to output a DC voltage, wherein the emergency supply unit is configured to detect an emergency situation and being configured to output a DC voltage higher than the DC voltage output by the power supply unit when the emergency situation is detected.

Abstract: A power conversion device including: a power conversion circuit including a voltage control type first semiconductor switching element configured to convert DC power to polyphase AC power; a brake circuit including a voltage control type second semiconductor switching element configured to protect the power conversion circuit from an overvoltage applied to the power conversion circuit; a control circuit configured to control the first semiconductor switching element in the power conversion circuit and the second semiconductor switching element in the brake circuit; and a snubber circuit including a resistor and a capacitor that are connected between a negative potential side of the power conversion circuit and a negative potential side of the control circuit and are configured to suppress a surge voltage.

Abstract: Disclosed is a brushless-motor drive apparatus provided with: a current detecting means (6) for detecting currents flowing through armature windings (9) during periods when switching elements (5H, 5L) of a drive circuit are ON; a calculation processing means for comparing a target current value and the detected current value, and calculating voltage command values to be applied to the armature windings (9); and a PWM driving means (4) for controlling the ON/OFF of the switching elements on the basis of the voltage command values.

Abstract: Provided are an emergency power supply method for a container terminal and a container terminal, which supply emergency electric power by using a cargo handling machine as a power source in an emergency situation due to electric outage of the container terminal, or the like. In an emergency where an incoming panel (2) of the container terminal (1) cannot supply electric power, yard cranes (11a) to (11c) (cargo handling machines) configured to operate in the container terminal (1) are used as power sources, in which one (the yard crane (11a)) of the plurality of yard cranes (11a) to (11c) (cargo handling machines) is used as a reference power source, and power conditioning units are included which configured to match phases of electric powers of the remaining yard cranes (11b) and (11c) to a phase of electric power of the reference power source, such that electric power is supplied from the plurality of yard cranes (11a) to (11c) to the incoming panel (2).

Abstract: A detection method for elevator brake moment solves the problems that operation of the brake detection device in the prior art is required to be manually executed, the brake detection device is not convenient and facilitative to operate, the function is singular and the brake moment change trend and the brake wear trend cannot be reflected. In the method, by inputting stagewise torque current to the motor and determine whether the torque during rotation of a motor is within the design moment range of a brake, whether torque of the brake is enough can be determined and the brake wear trend can be analyzed according to torque recorded at each time. The method has advantages that the automatic detection is performed periodically, the functions are diversified, the detection accuracy is high, the brake moment change trend can be reflected and the brake wear trend can also be reflected.

Abstract: A motor control device is provided with a control circuit and a driving circuit. The control circuit switches over a current supply phase of the motor in a predetermined angular rotation of the rotor a first switching number of times in an acceleration range. The control circuit switches over the current supply phase of the motor in the predetermined angular rotation of the rotor a second switching number of times in a stationary rotation range in a specific condition that the rotation speed of the rotor is between a predetermined first threshold value and a predetermined second threshold value. The control circuit sets the second switching number to be smaller than the first switching number. In the acceleration range, the switching number is relatively large and hence a sufficient driving torque is applied to the rotor.

Abstract: An overvoltage snubber circuit configured to receive an alternating current (AC) overvoltage includes a first rectifier configured to convert the AC overvoltage to a direct current (DC) overvoltage, a chopper circuit electrically connected to the first rectifier and configured to break up the DC overvoltage and to output a variable DC voltage, and a resistor electrically connected to the chopper circuit and configured to dissipate energy of the variable DC voltage.

Abstract: A motor drive device driving any of a feed shaft or spindle of a machine tool or arm of an industrial machine or industrial robot etc., comprising a current detecting part detecting a motor current, a current control part using an output from the current detecting part as the basis to output a command value to the motor, and a power converting part using a current command as the basis to supply power to the motor, the current detecting part comprising a current slope detecting part and a switching part using an output of the current slope detecting part to switch a plurality of filter characteristics to switch a mode of current detection. The switching part switches to a filter with a narrow/a broad bandwidth when the slope of the current is small/large to thereby improve the precision of current detection.

Abstract: A brake device having a block member, a first and second brake member movable relative to each other, and at least one adjustment member positioned between the block member and the first brake member to adjust the distance there between.

Abstract: A circuit configuration detects zero-crossings and/or a brownout condition. The circuit configuration contains a zero-crossing detection circuit, a brownout detection circuit, an isolation and digitization circuit connected to the zero-crossing detection circuit and the brownout detection circuit, and a filtering circuit connected to the isolation and digitization circuit. The single circuit configuration can be used for detecting zero-crossings of single-phase and multi-phase systems as well as ascertaining a brownout condition of either the single-phase or the multi-phase systems.

Abstract: A system including an electromagnetic braking system that has an eddy current brake. The eddy current brake includes an electrically conductive surface coupled to a shaft of a generator system, wherein the eddy current brake is configured to induce an electromagnetic force on the electrically conductive surface when powered. The electromagnetic braking system further includes a supercapacitor coupled to the eddy current brake, wherein the supercapacitor is configured to discharge to power the eddy current brake for the duration of a ride through event of the generator system, and the supercapacitor is configured to supply a threshold current to the eddy current brake within approximately 100 ms of a start of the ride through event.

Abstract: A hybrid vehicle includes a battery, a boosting converter, first and second inverters, a first inverter connected to the first inverter, a second motor generator connected to the second inverter, and a control unit configured to start and suspend the boosting converter. The control unit increases one or both of carrier frequencies Fc1, Fc2 of the first and second inverters as a real boost voltage VHr increases during a suspended state of the boosting converter. The control unit decreases one or both of the carrier frequencies of the first and second inverters as real boost voltage VHr decreases during a suspended state of the boosting converter. System efficiency of an electric vehicle can be improved effectively by increasing the suspension time of the boosting converter, while securing drivability of the vehicle.

Abstract: A method and circuit for starting a three-phase motor in a manner that reduces inrush current normally associated with starting an AC motor. The method uses the circuit to start the three phase motor gradually with three phase alternating current having relatively low frequency and gradually increasing the frequency up to or above the motor operating frequency over a period of time and then switching in a single phase alternating current supply to power the three phase motor.

Abstract: The present invention specifies a converter for an electrical machine. A power circuit breaker (T1) comprises at least two semiconductor elements (9, 10) connected to one another to form said power circuit breaker. At least one control circuit (C1, C2, 14) is associated with the at least one power circuit breaker (T1) and is connected to a respective control input of each of the at least two semiconductor components (9, 10) in order to selectively switch the same on and off by means of respective switching signals (S1, S2). The switching signals (S1, S2) are generated on the basis of switching losses and conduction losses of the power circuit breaker (T1).

Abstract: A method of controlling an electric motor (motor) includes providing a processor having an associated memory storing a stator resistance (Rs) estimation (RSE) algorithm that is programmed to implement the RSE algorithm to execute steps including injecting a current waveform at an arbitrary frame of reference into the stator using a field-oriented-control (FOC) motor controller including an Id controller and an Iq controller, and measuring current and voltage values from the motor responsive to the injecting. The measured current and voltage values are then transformed into transformed current and voltage values in a d/q coordinate system. The transformed current and voltage values are low pass filtered to generate filtered d/q current and voltage values, and a value for Rs is estimated from the filtered d/q current and voltage values. The arbitrary frame of reference can be a time-varying frame of reference.

Abstract: In one embodiment, an elevator controlling method includes calculating the positional value of an elevator driving motor the every first cycle; generating a control signal every third cycle to control the motor based on the calculated positional value and the rotational speed of the motor calculated every second cycle; and controlling the driving power source of the motor based on the generated control signal.

Abstract: A method for controlling movement of an elevator car during an emergency stop includes the steps of determining the load of the car; determining the travel direction of the car; and monitoring the speed of the car. When the car is determined to be either lightly loaded and travelling downwards, or heavily loaded and travelling upwards, brake torque is applied only when the speed of the car reaches zero, as slowing of the car can be accomplished solely by virtue of the balancing factor of the car's counterweight.

Abstract: An exemplary power supply assembly includes a drive device having a bus capacitor. A switch associated with an input side of the drive device selectively connects the drive device to a power supply. An inductor has an impedance that limits an amount of current supplied to the bus capacitor during an initial charging of the bus capacitor when the switch connects the input side of the drive device to the power supply. A restrictive circuit portion dampens a resonance effect of the inductor. The restrictive circuit portion has a resistance that allows the bus capacitor to charge quickly. The impedance of the inductor has a more significant effect on how quickly the bus capacitor charges than an effect of the resistance. A dampening factor of the restrictive circuit controls a voltage of the bus capacitor during the charging of the bus capacitor.

Abstract: A system continuously drives a motor during normal and power failure operating conditions. A regenerative drive delivers power to the motor from a main power supply during the normal operating condition and from a backup power supply during the power failure operating condition. A controller operates the regenerative drive to provide available power on the regenerative drive to the backup power supply during the normal operating condition.

Abstract: A suspension work platform hoist system powered by an input power source for raising a work platform on a rope. The system includes a hoist having a motor that drives a traction mechanism designed to cooperate with the rope, and a reactive power reducing input power system in electrical communication with the motor and the constant frequency input power source. The reactive power reducing input power system includes an AC-DC converter and a regulator system, wherein the regulator system is in electrical communication with a DC-AC inverter that is in electrical communication with the motor. The system may include an isolation system to electrically isolate the DC-AC inverter from the motor when the DC-AC inverter is not transmitting power to the motor. The system may accept multiple alternating current voltage sources including both single phase and three phase sources.

Abstract: A power conversion apparatus includes: a line breaker that is connected in series to a direct-current power supply; a first capacitor that is connected in parallel to the direct-current power supply through the line breaker; a discharge circuit that includes a resistor and a first switching circuit connected in series and is connected in parallel to the first capacitor; a power converter for driving a synchronous machine; a second capacitor that is connected in parallel to a direct-current side of the power converter; a second switching circuit that is connected in series between the first capacitor and the second capacitor; and a control circuit for controlling the discharge circuit. The control circuit controls the discharge circuit on the basis of the voltage of the first capacitor and the voltage of the second capacitor.

Abstract: A suspension work platform hoist system having reduced reactive power to produce a hoist system power factor of at least 0.95 when operating at a steady state full-load condition as the motor raises the work platform. The hoist system power factor takes into account all the power consuming devices of the suspension work platform hoist system as well as a suspended conductor system that connects the constant frequency input power source to the hoist, which is often in excess of several hundred feet. The hoist system power factor may be achieved by incorporating a reactive power reducing input power system into the suspension work platform hoist system. The reactive power reducing input power system decreases the magnitude of the reactive power of the motor producing a high hoist system power. The reactive power reducing input power system may include an AC-DC converter and a regulator system in electrical communication with a DC-AC inverter that is in electrical communication with the motor.

Abstract: The invention relates to a variable speed drive comprising a direct-current power bus having a positive line (16) and a negative line (17), and an inverter module (14) supplied by the direct-current bus in order to supply a variable voltage to an electric load (M). The drive comprises an energy-recovery device (10) comprising a first direct-current/direct-current converter (20), the output stage of the first converter (20) being connected in series to the positive line of the direct-current bus, a second direct-current/direct-current converter (30), the input stage of the second converter (30) being connected between the positive line and the negative line of the direct-current bus, and an electric energy storage module (Cs) connected in parallel with the input stage of the first converter (20) and with the output stage of the second converter (30).

Abstract: A system (10) continuously drives an elevator hoist motor (14) during normal and power failure operating conditions. A regenerative drive (30, 34, 36) delivers power to the hoist motor (14) from a main power supply (17) during the normal operating condition and from a backup power supply (24) during the power failure operating condition. A controller (12) operates the regenerative drive (30, 34, 36) to provide available power on the regenerative drive (30, 34, 36) to the backup power supply (24) during the normal operating condition.

Abstract: A suspension work platform hoist system for raising and lowering a work platform is provided. The system incorporates at least one hoist attached to the work platform and in electrical communication with a motor control system. The motor control system is attached to the work platform and is in electrical communication with a constant frequency input power source and the hoist motor. The motor control system controls the acceleration of the work platform as it is raised and lowered by controlling the hoist motor. The system may further include a tilt control system to allow the work platform to reach and maintain a tilt angle setpoint as the work platform is raised and lowered, and/or a system to reduce the reactive power associated with its operation.

Abstract: An elevator control device includes a vector controller that calculates a voltage command required for driving an elevator cage, a carrier frequency switch circuit that outputs a carrier frequency signal, and a power converter that performs PWM control based on the voltage command and the carrier frequency signal, generates an AC power and supplies the AC power to an AC motor. The carrier frequency switch circuit changes the carrier frequency signal when a torque command for driving the AC motor reaches a torque limit value. Thus, it is possible to continuously operate an elevator without causing damage to a switching element of the power converter.

Abstract: An elevating machine control apparatus controls an inverter (4) to drive an AC motor (5) connected to the inverter (4) with AC power, and energizes a power generation braking resistor (13) to apply a brake during regenerative operation of the AC motor (5). The apparatus prohibits the elevating machine from starting operating and interrupts power supply to the power generation braking resistor (13) if the DC stage voltage of the inverter (4) has a ripple quantity of a set value or more when the elevating machine is being stopped. Alternatively, the apparatus commands the elevating machine to stop operating and interrupts power supply to the power generation braking resistor (13) if the DC stage voltage of the inverter (4) during regenerative operation is a reference value or less when the elevating machine is in operation.

Abstract: A powered controlled acceleration suspension work platform hoist system for raising and lowering a work platform at a predetermined acceleration. The system incorporates several hoists attached to the work platform and in electrical communication with the motor control system. The motor control system is attached to the work platform and is in electrical communication with a constant frequency input power source and the hoist motors. The motor control system controls the acceleration of the work platform as it is raised and lowered by controlling the hoist motors. The controlled acceleration hoist system also includes a platform control system attached to the work platform that is in electrical communication with the motor control system and the hoist motors. Acceleration control is achieved by converting the constant frequency input power to a variable frequency power supply. This may be accomplished through the use of a variable frequency drive(s).

Abstract: In addition to the construction of a typical elevator control device in which power generated during regenerative operation is dissipated by a resistance chopper (18), an elevator control device is newly provided with: an electric double layer capacitor (21) connected in parallel with the DC capacitor (3) that smoothes the DC ripple of the rectifier circuit (2) that rectifies the AC power of the AC power source (1) and having an electrostatic capacitance that is considerably larger than this DC capacitor; a voltage detection circuit (22) that detects the terminal voltage of this electric double layer capacitor; and a drive control unit (5) that uses a voltage in the vicinity of the rated voltage of the electric double layer capacitor as the operating voltage of resistance chopper and, when the terminal voltage detected by a voltage detection circuit reaches the voltage in the vicinity of the rated voltage of the electric double layer capacitor, operates and controls the resistance chopper.

Abstract: The present invention provides an elevator controller including: a main control unit for controlling running of an elevator, in which the main control unit predictively calculates a continuous temperature state of a predetermined componential equipment of the elevator and performs an operation control of the elevator based on the predicted temperature state such that the componential equipment is not overloaded. Accordingly, a temperature rise in the componential equipment is suppressed, thereby enabling to prevent the elevator from becoming inoperable.

Abstract: An operation device for an elevator system includes terminals connectable to a 3-phase AC power source providing a respective AC power supply voltage and a drive device connected to the terminals for driving a motor of the elevator system. A transformer is connected to at least two of the terminals and provides at least one supply voltage to the remainder of the elevator system. In an emergency operation of the elevator system, an auxiliary power supply having an output providing an auxiliary output voltage is connected to the transformer for generating an auxiliary supply voltage provided to the drive device via the transformer.

Abstract: The hoist control cooling system for preferentially cooling components of a variable frequency drive that is controlling a hoist motor. The cooling system includes an inverter temperature sensor, an ambient temperature sensor, a cooling system controller, an inverter cooler, and an ambient cooler. The inverter temperature sensor measures the temperature of the inverter and generates an inverter temperature signal. The ambient temperature sensor measures the temperature of the ambient air in the sealed control enclosure and generates an ambient temperature signal. The cooling system controller communicates with the inverter temperature sensor and the ambient temperature sensor by receiving the inverter temperature signal, the ambient temperature signal, and generating both an inverter cooling signal, and an ambient cooling signal. The inverter cooling signal controls the cooling of the inverter.

Abstract: A car is suspended by suspension means and raised and lowered by means of a hoisting machine. Electric power supplied to a motor of the hoisting machine is controlled by an electric power converter. The electric power converter is controlled by means of a control apparatus. The control apparatus estimates a maximum value of a regenerative voltage at time of a regenerative operation of the hoisting machine when the car is running. When the estimated maximum value of the regenerative voltage reaches a predetermined voltage limit value, the control apparatus controls the electric power converter so as to stop an increase in estimated maximum value of the regenerative voltage.

Abstract: A powered controlled acceleration suspension work platform hoist system for raising and lowering a work platform at a predetermined acceleration. The system incorporates several hoists attached to the work platform and in electrical communication with the motor control system. The motor control system is attached to the work platform and is in electrical communication with a constant frequency input power source and the hoist motors. The motor control system controls the acceleration of the work platform as it is raised and lowered by controlling the hoist motors. The controlled acceleration hoist system also includes a platform control system attached to the work platform that is in electrical communication with the motor control system and the hoist motors. Acceleration control is achieved by converting the constant frequency input power to a variable frequency power supply. This may be accomplished through the use of a variable frequency drive(s).

Abstract: A powered controlled acceleration suspension work platform hoist system for raising and lowering a work platform at a predetermined acceleration. The system incorporates several hoists attached to the work platform and in electrical communication with the motor control system. The motor control system is attached to the work platform and is in electrical communication with a constant frequency input power source and the hoist motors. The motor control system controls the acceleration of the work platform as it is raised and lowered by controlling the hoist motors. The controlled acceleration hoist system also includes a platform control system attached to the work platform that is in electrical communication with the motor control system and the hoist motors. Acceleration control is achieved by converting the constant frequency input power to a variable frequency power supply. This may be accomplished through the use of a variable frequency drive(s).

Abstract: A powering arrangement (32, 34) for a device (30, 22) that normally operates on three phase power has the capability of operating based upon single phase power. One disclosed technique includes estimating a direct component based upon a measured voltage across the leads coupled with the single phase power supply. The quadrature component is estimated based upon a numerical derivative of the direct component. The direct component is also provided to a current regulator in a feed forward control manner, which minimizes error.

Abstract: A set of elevators, preferably an elevator group, may include a number of elevators without counterweight which have a common connection to a power supply. The elevators may have a common control system which contains an instruction to prevent an elevator having stopped at a floor from being dispatched upwards if, of the elevator cars of the other elevators connected to the same power supply, more cars are moving upwards than are moving downwards at the instant and/or within a set period of time. A method for controlling a set of elevators without counterweight connected to a common power supply may include monitoring to establish whether, at the instant and/or within a set period of time, the number of upwards moving elevator cars of the elevators in the set is larger than the number of downwards moving elevator cars of the elevators in the set.

Abstract: A power control system is operable for controlling and balancing the generation and/or consumption of electrical power through an internal electricity distribution network connected with at least one electrically driven elevator system. The elevator system is connected to the internal electricity distribution network of a particular building, which can further be connected either to the external public electricity distribution network, or to a reserve power appliance. An elevator system includes at least one elevator, an elevator control system, an elevator motor, a frequency convertor fitted to supply the elevator motor which may be in operation when provided with electricity through an external public electricity distribution network, or during disruption of power.

Abstract: In a feeder circuit for operating a safety device of an elevator, a charging capacitor for actuating an actuator through discharge is employed. A failure detecting device for detecting the presence or absence of a capacitance shortage of a charging capacitor is also electrically connected to the feeder circuit. The failure detecting device has a memory in which a lower limit and upper limit of a charging time at the time when the charging capacitor is in normal operation are stored, and a CPU which is capable of measuring the charging time of the charging capacitor and detects whether or not the charging time is between the lower limit and the upper limit. When the charging time is between the lower limit and the upper limit, the CPU determines that there is no capacitance shortage of the charging capacitor.

Abstract: An elevator drive assembly (30) includes a voltage regulator (40) that selectively introduces current under certain conditions. In one example, the voltage regulator (40) introduces a negative flux current to an electric motor (32) when the motor (32) is operating under conditions corresponding to constant speed movement of an elevator car (22). In one example, the added negative flux current effectively reduces the back-EMF voltage of the motor (32) during the constant velocity portion of an elevator run. A disclosed example includes controlling the added current to maintain control over a motor torque constant, which becomes a function of the added current.

Abstract: The invention is directed to an apparatus and methods for enhancing the energy efficiency of a variable speed drive (VSD) used to control an elevator by disconnecting the VSD from the AC power supply grid when the elevator is idle and reconnecting the VSD when the elevator becomes active. One embodiment of the invention includes an alternating current power supply grid, one or more variable speed drives, contactors connected between the alternating current power supply grid and the variable speed drive(s) that are used to connect or disconnect the variable speed drive(s) from the alternating current power supply grid, and, a control system that controls the contactors. The contactors may include a coil which is powered by the control system to either connect or disconnect the VSDs and the AC power supply grid.

Abstract: A motor driving apparatus applicable to various types of motor driving apparatuses and having a power storage section for storing a regenerative current and supplying power to an inverter section at the time of acceleration. The motor driving apparatus further comprises a converter section, a DC link, and an inverter section, thereby driving a motor. Connected to the DC link is the power storage section including a capacitor, a charging circuit, a discharging circuit and a diode. The regenerative current produced at the motor deceleration is stored in the capacitor through the diode. The power stored in the capacitor is outputted to the DC link by turning a switching element of the discharging circuit ON at the motor acceleration. Furthermore, the charging circuit has a boost switching regulator circuit for charging the capacitor to the given upper limit voltage equal to or larger than voltage of the DC link and a current limitation circuit for limiting a charging current to the given upper limit.